Sign in to the airline or ticketing site where you purchased tickets. This usually requires entering a username and password.
Access the personalized trip list of your airline or ticketing website. The list may be named "My Trips," My Itineraries" or "My Flights," for example. Typically, you can access it by clicking on the list name that usually appears at the top of the screen.
Select the "Check-In" option. This option will be disabled if online check-in is not possible. The resulting screen will display the first of your flights to your end destination.
Select the number of passengers and the number of bags to be checked, if any. If your airline requires a fee to check bags, payment options will be displayed.
Choose the "Select Seats" option. The resulting screen displays a top-down view of the plane's seating layout. You will see a key near the top of the screen that lets you know how available seats are denoted.
Click on the available seat of your choice. This screen may also give you an option to upgrade to a different seating section, usually upon payment of an additional fee.
Repeat this process for any connecting flights to your destination.
Turn on your printer and be sure it is equipped with enough paper to print your flight documents.
Select "Print Boarding Pass(es)."
Check the printed boarding passes for accuracy as to flight number, reservation number, date and destination.
